Measuring instrument.



LE ROY J. LEISHMAN.

MEASURING INSTRUMENT.

APPLICATION FILED OCT. 21, 1914.

Patented May 2, 1916.

2 SHEETSSHEET I.

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1 P N .w E W 5 LE ROY J. LEISHMAN.'

MEASURING INSTRUMENT.

APPLICATION FILED OCT. 21, 1914.

Patented May 2,1916.

2 SHEETSSHEET 2- LE ROY J. LEISHMAN, OF OGDEN, UTAH.

MEASURING INSTBUMEN Application filed October 21, 1914.

To all whom it may concern:

Be it known that I, Ln ROY J LEISHMAN, a citizen of the United States,residing at Ogden, in the county of Weber and State of Utah, haveinvented new and useful Improvements in Measuring Instruments, of whichthe following is a specification.

This invention relates to measuring instruments, and particularly to adevice whereby the arc of a circle may be measured for the purpose ofdetermining the diameter of the particular circle of which such are isan arc, and also for the purpose of determining the number of degrees inthe arc in question.

The object of the invention is to provide an instrument of the characterand for the purpose described whereby the operations stated may beeasily and quickly carried out without the necessity of the operatordoing any mathematical work whatever.

The invention consists of the features of construction, combination andarrangement of parts herein fully described and claimed, reference beinghad to the accompanying drawings in which Figure 1 is a face view of ameasuring instrument embodying my invention. Fig. 2 is a similar view ofa portion of the instrument on an enlarged scale and indicating its modeof use. Fig. 3 is a view of a modified form of instrument.

The instrument comprises a body 1 which is preferably in the form of asubstantially triangular plate, of metal, wood, celluloid or any othersuitable material. This body portion is provided with a transverselyextending diameter scale 2 and a longitudinally extending distance scale3, the firstnamed scale containing figures for indicating diameters from1 to 10 inches, in inches and fractions thereof, while the scale 3contains a row of numerals for indicating linear distances from 1 to 10inches in inches and fractions thereof. These scales are arranged alongtwo of the sides of a triangular field or space which is subdivided bysets of lines running at right angles to each other into columnsintersecting the diameter and distance numerals, and in which arearranged figures indicating the number of degrees in an arc of a circleof any radius within the measuring range of the instrument.

The body 1 is provided with a plurality of are and diameter indicators4;, 5, 6 and Specification of Letters Patent.

Patented May 2, 1916.

Serial no. senses.

7 formed by cutting out portions from a pro ecting portion 8 of thebody, each of said indicators including a diameter measmg line 9terminatin in indicating points 10, a straight edge 11 arranged at rightangles to the said line 9, and a diameter scale 12. In the presentinstance, I have shown the use of four angle indicators, which arearranged upon the longer side or base of the body. vided scales thus aregraduated scales of different sizes and having different measuringdegrees, the distances between the measuring points 10 and the lengthsof the scale edges of which vary progressively throughout the series ofscales. As shown, each of these are and diameter indicators has itsscale 12 formed of lines intersecting the edge 11 at different distancesfrom the line 9 and leading to angle indicating numerals. Theseindicating lines are so disposed as to extend tangentially to the arc Aof a circle whose diameter is being measured, as illustrated in Fig. 2,illustrating the mode of use of the instrument. It is to be understood,of course, that the diam eter indications and scale marks upon therespective are and diameter indicators are based upon the distancesbetween the indieating points 10, which are designed to in dicate andare based upon the chord length of the arc of the circle from the centerof which the arc is struck.

The instrument is designed to be placed upon the arc of a circle toindicate the di ameter of the particular circle of which such are is anarc, and also to indicate the number of degrees in the said are, whichoperations have heretofore been performed without the use of aninstrument and by means of very accurate mathematical work.

The instrument, as shown, measures arcs containing from about 40, assmall as any one ordinarily would ever desire to measure, up to 180.180, there would be no need of using the instrument, as the diametercould easily be told by measuring with a rule. The particular instrumentillustrated will measure arcs whose circles range from 1 to 10 inches indiameter, but the measuring range of the device may be increased ifdesired.

In the use of the device for determining the diameter of a particularcircle of which any certain arc is an arc, the base line 9 of the properindicating member is disposed The indicators and pro- If the arccontains more than across the are as shown in Fig. 2, so that its points10 touch the sides of the arc, and so that the arc will be intersectedby one of the tangential scale lines, the numeral associated with whichwill denote the diameter of the circle of which the are is an are. Asshown in Fig. 2, the are illustrated shown as being an arc of a circlehaving a diameter of three inches. Of course, it will be understood thatthe largest of the four measuring scales that may be used upon the arewill be employed. Thus by means of the measuring scales or indicatorsthe diameter of any circle of which any are is an arc, within the rangeof the instrument, may be readily and conveniently determined withoutmathematical calculation.

The scale 12 may also be used for other mathematical calculations suchas finding the degrees formed by the hypotenuse and base of a righttriangle, by locating the inches and fractions of inches contained inthe hypotenuse on the diameter indicating row of figures and the lengthof the altitude on the distance indicating row, and proceeding as infinding the degrees in an arc.

If it should be desired to find the 11111111181. of degrees in the are,the distance between the extremities of the are along the chord line ismeasured by means of the rule, on the instrument, and this is followedout by finding the distance indicating figures in the scale 8 and thenfinding the numeral in the degree table which is disposed at the pointof intersection of the distance indicating row of figures and thediameter indicating row of figures, in which space of the table will befound the numeral indicating the number of degrees in the measured are.

In Fig. 3 of the drawings I have shown a modified construction ofinstrument, which is adapted to be folded and conveniently carried inthe pocket. This instrument com prises a pair of measuring strips orblades 13 and 14, and an indicating strip or blade 15, all of whichblades are pivotally con nected at one end, as indicated at 16, so thatsaid blades may be folded in parallel relation or the two blades 13 and1 1 unfolded in longitudinal alinement and the blade 15 disposed atright angles thereto, thus setting (topic; 01 this patent may beobtained for five cents each, by addressing the "Commissioner ofPatents.

the instrument ready for use. Vhen the blades are unfolded or set foruse, the blade 15 abuts against the stop pin 16 carried by the blade 13,when it is arranged in proper relative position to the blades 13 and 14.The alined inner edges of the blades 1.3 and 1 1 form the base line 9having terminal indicating points 10, while one edge of the blade 15forms a straight edge 11, and said blade is provided with the diameterscale 12. The mode of use of this instrument will be readily understoodfrom the foregoing description.

I claim 1. An instrument of the character described comprising a bladeformed with a triangular cut-away portion, one of the arms of saidportion forming a st 'aight edge and the other an indicating line, saidstraight edge and indicating line terminating at their relatively outerends indicating points, said blade being further provided with scaleindications along said indicating line for cooperation with theindicating point of the straight edge, and a second indicating pointupon the blade on the side of the indicating line opposite to thefirst-named indicating point.

2. An instrun'ient of the character described comprising a bladeprovided with a series of graduated scales for indicating the number ofdegrees in an arc and the dianr eter of the particular circle of whichsuch are is an are, each scale having a certain range of measuremnt, andeach comprising triangular cut away portion forming a base line orstraight edge and a scale line constituting two of the sides of the saidportion, the base line having an indicating point at its end remote fromthe indicating line, and said blade being provided with graduated degreeindicia along the indicating line, and an indicating point upon theblade on the opposite side of the indicating line from the indicatingpoint of the base line.

In testimony whereof I aflix my signature in presence of two witnesses.7

LE ROY J. LEISHMAN.

Vitnesses DAVID J ENSON, LEO A. HARRIS.

Wuhlngton, D. 0.

